Field of Invention
The present invention relates to a rotor housing cover assembly for a combine harvester, the cover assembly comprising first and second curved cover plate sections, at least one of which sections forming an upper part of a generally cylindrical shaped rotor housing for a crop processing rotor.
Description of Related Art
Axial-flow or rotary combine harvesters usually have one or two crop processing rotors having a rotation axis which is substantially parallel to the longitudinal axis of the harvester. In some machines the rotors perform both the threshing and separating action upon the cut crop flow delivered thereto. In other machines, such as ‘hybrid’ machines, a tangential-flow threshing cylinder is employed upstream of the rotors, wherein the rotors themselves serve a subsequent separating function.
Each crop processing rotor is mounted in a respective rotor housing which is generally cylindrical and which includes a grate or concave in the lower section to allow separated grain to fall onto an underlying collection pan. Enclosing curved cover assemblies are provided in an upper section of the housing.
Crop material is fed into a front inlet section of the rotor housings where the crop material is engaged by flighting elements on the rotor. The crop material is conveyed as a ribbon or mat in a generally rearward axial and helical path in the space between the rotor and the rotor housing. Axial conveyance of the crop material is driven by the interaction between helical guide vanes provided on the inside surface of the upper cover plates and threshing and separating elements provided on the rotor. Threshing of the crop material and the subsequent separation of the grain therefrom is mostly carried out in the lower portions of the helical path by the interaction between the threshing and separating elements respectively and the concave, the space between which is adjustable. Separated crop material passes by gravity through the grate whereas the longer bulkier straw residue is conveyed via an outlet or discharge section at the rear of the housing.
The cover plates are substantially half cylindrical in shape and are mounted along respective outer and inner longitudinal edges to fixing points provided by the machine frame. Flanges are often provided along the edges of the cover plates so as to provide means of fastening to the frame by bolts.
For the sake of maintenance convenience it is known for the cover assembly to be formed from two separable cover plate sections; a front section and a rear section. It is also known to provide a seam between the cover plate sections that is angled with respect to the circumference of the housing so that the seam lays parallel with the angle of the guide vanes, thus avoiding the guide vanes intersecting the seam.
In order to separate the two cover plate sections there is a need for access from above the rotors. On some combine harvester architectures access from above the rotors is convoluted and difficult to achieve.